THE USE OF CRYOPRESERVATION IN THE EX-SITU CONSERVATION OF FUNGI

Microbial genetic resources are collected and stored for many differen t reasons providing an organism base for future use and reference to s upport science and industry. There are almost 500 collections world-wi de registered with the World Data Center for Microorganisms (WDCM). Ho wever, of the estimated 1.5 million fungi only 72000 strains have been described and less than 20% of these are held in collections. It is a lso evident that many microorganisms have only been isolated once as a lmost 50% of the species held by the WDCM collections are represented by one isolate only. Storage at ultra-low temperature has an essential role to play in securing these organisms for sustainable use. A two s tep method of cooling was initially employed which approximated -1 deg rees C min(-1). Improved viability and stability was achieved by using linear cooling rates determined by cryogenic light microscopy.